6AUO

Artificial Metalloproteins Containing a Co4O4 Active Site - 2xm-S112F

Summary for 6AUO

• Entry DOI: 10.2210/pdb6auo/pdb
• Descriptor: Streptavidin, N-biotin-C-Co4(mu3-O)4(Py)3(H2O)4-beta-alanine (3 entities in total)
• Functional Keywords: streptavidin, biotin, artificial metalloprotein, co4o4, photosynthesis, water oxidation, biomimetic, metal binding protein
• Biological source: Streptomyces avidinii
• Total number of polymer chains: 1
• Total formula weight: 17487.44

Authors

Olshansky, L.,Vallapurakal, J.,Huerta-Lavorie, R.,Nguyen, A.I.,Tilley, T.D.,Borovik, A.S. (deposition date: 2017-09-01, release date: 2018-02-28, Last modification date: 2023-10-04)

Primary citation

Olshansky, L.,Huerta-Lavorie, R.,Nguyen, A.I.,Vallapurackal, J.,Furst, A.,Tilley, T.D.,Borovik, A.S.
Artificial Metalloproteins Containing Co
J. Am. Chem. Soc., 140:2739-2742, 2018

PubMed Abstract: Artificial metalloproteins (ArMs) containing CoO cubane active sites were constructed via biotin-streptavidin technology. Stabilized by hydrogen bonds (H-bonds), terminal and cofacial Co-OH moieties are observed crystallographically in a series of immobilized cubane sites. Solution electrochemistry provided correlations of oxidation potential and pH. For variants containing Ser and Phe adjacent to the metallocofactor, 1e/1H chemistry predominates until pH 8, above which the oxidation becomes pH-independent. Installation of Tyr proximal to the CoO active site provided a single H-bond to one of a set of cofacial Co-OH groups. With this variant, multi-e/multi-H chemistry is observed, along with a change in mechanism at pH 9.5 that is consistent with Tyr deprotonation. With structural similarities to both the oxygen-evolving complex of photosystem II (H-bonded Tyr) and to thin film water oxidation catalysts (CoO core), these findings bridge synthetic and biological systems for water oxidation, highlighting the importance of secondary sphere interactions in mediating multi-e/multi-H reactivity.

PubMed: 29401385
DOI: 10.1021/jacs.7b13052

Experimental method

X-RAY DIFFRACTION (1.7 Å)